UPD17062 datasheet(124/298 Pages) RENESAS

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µPD17062

11.7.2

Functions

An interrupt can be issued when either a rising or falling edge is input to the INTNC or VSYNC pin.

Use the IEGNC or IEGVSYN flag in the interrupt edge select register of the control register to select the rising

or falling edge.

Table 12-2 shows the relationship between the IEGNC and IEGVSYN flags and the active edges of interrupt

requests.

Note the following:

If the IEGNC or IEGVSYN flag is used to switch the interrupt request edge, an interrupt request signal may

be issued at the moment of switching.

Suppose that the IEGNC flag is set to 0 (falling edge) and a high level is input to the INTNC pin as shown

in Table 11-3. At this time, if the IEGNC flag is set to 1, the edge detector determines that a rising edge has

been input and therefore issues an interrupt request.

See Section 11.2 for operations after interrupt request issuance.

Because the signals input to the INTNC and VSYNC pins are input to the INTNC and INTVSYN latches as shown

in Fig. 11-5, the input signal levels can be detected by reading the INTNC and INTVSYN flags.

Because the INTNC and INTVSYN flags are set or reset regardless of interrupts, they can be used as 2-bit

general-purpose input ports when the corresponding interrupt functions are not used.

If interrupt is not permitted, the flags can be used as general-purpose ports that can detect a rising or falling

edge by reading the interrupt request flags (IRQNC or IRQVSYN). However, because the interrupt request flags

are not automatically reset in this case, they must be reset by the program.

Table 11-2

IEGNC and IEGVSYN Flags and Interrupt Request Issuance Edges

IEGNC

Flag values

INTVSYN

Active edges of interrupt

request pins

VSYNC pin

INTNC pin

Rise

Fall

Rise

Fall

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